Abstract:

Dead fuel moisture content (DFMC) prediction is a very important component in fire danger rating,its accuracy becomes the crucial determination of fire behavior and fire weather forecasting.Methods for predicting DFMC based on equilibrium moisture content (EMC),are physically precise and reliable if the study objects could be described exactly.Therefore,they are the most important methods in DFMC prediction.The theoretical basis of the methods and their applications are reviewed in the paper.The results indicate as below:1) There are four major EMC models among which Simard model,Van Wagner model and Anderson model are all empirical with limited application,whereas Nelson model is semi-physical one and has been used widely.2) Although EMC is affected by fuel type,systematic research on this area has not been conducted yet. 3) Although few studies on factors affecting timelag have been carried out,it is still sure that fuel types, fuel physical characteristics can affect fuel timelag. 4) Catchpole et al. Method,which was based on Nelson model,has been used widely and opened up a vast range of prospect for making use of EMC and timelag.5) EMC and timelag had become the foundation for DFMC prediction in NFDRS of the United States and CFFDRS of Canada and other like systems.

Key words: timelag, equilibrium moisture content, fuel, prediction